Method of installing

ABSTRACT

A roller bearing installation, in which one or more roller bearing assemblies (30A, 30B, 30C) are prepackaged in a housing (18) having corresponding recesses (28A, 28B, 28C) receiving each bearing assembly (30A, 30B, 30C). An angled gib plate (52A, 52B, 52C) is bedded in each recess, each gib plate (52) including an inclined section (54) mating with an inclined surface (58) on a bearing assembly cover (72) to allow a bearing depth adjustment by lengthwise adjustment of the bearing assembly (30) in its recess, enabling position adjustment of the supported structure (10) and bearing preload adjustment. Accurate alignment of the bearing assembly (30) is achieved by a ball plunger (100) urging the same against a guide surface (57) of the gib plate (52). A fixture (110) is used to precisely locate each gib plate (52A, 52B, 52C) in a recess (28) whjile a moldable bonding material (109) in which each gib plate (52) is bedded sets up. Electromagnetic coils (146, 148) are used to releasably hold each gib plate (52) on a respective locator arm (134, 136) during the process.

This application is a division of application Ser. No. 925,208, filedOct. 31, 1986, now U.S. Pat. No. 4,730,945, issued Mar. 15, 1988.

FIELD OF THE INVENTION

This invention concerns installation of way bearings as are used insupporting machine tool structures for linear motion on way surfaces,and more particularly installations of way bearings of the recirculatingroller type.

BACKGROUND DISCUSSION

In machine tools and other similar machines and apparatus it is oftennecessary to support relatively heavy structural components forprecision movement along way surfaces.

The accuracy of machining depends on the accuracy of the motion of suchcomponents along their respective axis.

Simple plain bearings, used for many years, have more recently beenreplaced by various linear roller bearings in order to reduce friction.A successfull version of such bearings is the so called recirculatingroller bearing in which a series of roller elements move about acirculation path accurately ground into the periphery of a track member,with a surrounding and enclosing bearing cover confining the rollers intheir recirculation path. The roller elements are exposed on one side ofthe bearing assembly such as to enable rolling movement along a waysurface with the supported structure mounted to the bearing cover.

In order to achieve the accurate linear motion, the axis of the bearingassembly must be precisely aligned with the desired direction of motionof the supported structure, and this also prevents skewing forcestending to reduce bearing life.

In U.S. Pat. No. 4,544,211 entitled "RECIRCULATING BEARING ASSEMBLY"issued on Oct. 1, 1985, there is disclosed an improved recirculatingroller bearing in which skewing forces are minimized in the bearingassembly.

Two sets of roller elements each circulate about the track member oneither side of a central divider.

Installation of such bearing assembly in the supported structuretypically involves precision machining of locating surfaces in order toproperly align the bearing assembly within the supporting structure.

There is oftentime a need to provide adjustability of the bearing depthand in such instances a gib wedge plate package is provided in which apair of plates having matching inclined surfaces are adjusted lengthwiserelative to each other in order to provide a adjustment of the depth ofthe installed bearing assembly.

Such bearing assemblies are typically installed in sets, each comprisedof a number of variously facing bearings such as to engage a series ofsurfaces on the supporting structure, such as above and below a waysurface and along a lateral edge. In such instances it is usual toprovide such bearing adjustment for enabling precision adjustment of asupported structure and also for establishing a proper bearing preloadby adjusting an opposing bearing assembly for reasons well known tothose skilled in the art.

In such installations, considerable precision machining of the supportedstructure is necessitated which is difficult and expensive to accomplishon the usually relatively massive supported structures. Typically, as ona table, saddle, column, or similar structure, four sets of bearingassemblies are necessitated, one at each corner of the table.

Additionally, assembling the supported member carrying the bearing setsonto the supporting ways is a difficult operation.

Such recirculating bearing assemblies need to be lubricated in use andsuch installations necessitate additional machining and assembly laborto direct lubrication passages to each of the bearings in each set alsoadding to the manufacturing cost.

As noted, it has heretofore been known to provide an adjustment in suchbearing assemblies by means of a pair of gib plates which are inclinedand mate with each other disposed atop the bearing assembly such thatlengthwise adjustment therebetween produces a height adjustment in thebearing assembly.

This arrangement typically includes a central slider or keyway with akey to maintain the perfect alignment of the bearing axis during theheight adjustment.

It is also known to simply use a shim disposed above the bearingassembly in the housing. This likewise requires precision machining ofthe supported structure to fit the gib plate assembly into thesupporting structure and the bearing assembly housing.

In order to simplify the assembly of the bearing housing onto the ways,separate bolted on sections are utilized, each having to be separatelymachined and precision aligned with the remaining structure.

U.S. Pat. No. 4,486,054 issued on Dec. 4, 1984 for a "RECIRCULATINGROLLING BEARING" disclosed an adjustable roller bearing assembly inwhich a cylindrical bearing housing is slidably fit into a bore slightlyinclined to the bearing to enable a height adjustment. This requires aprecision machined bore.

DESCRIPTION OF THE INVENTION

The present invention is an improved installation for a roller bearingassembly comprising a housing structure formed with a recess configuredto receive the bearing assembly and with the bearing assembly covermember formed with an inclined upper surface, which mates with aninclined surface formed on a section of an angled gib plate fixed withinthe recess. The angled gib plate is also formed with a straight guidesection.

The housing is installed in the recess urged against the guide sectionto precisely align the axis of the bearing throughout a lengthwiseposition adjustment of the bearing assembly, executed in order toproduce a depth adjustment of the bearing assembly by mating of theinclined surfaces of the bearing cover and gib plate inclined section.

The angled gib plate is preferably secured in the recess in a fixedpredetermined position by means of a moldable bonding material appliedwhile holding the gib plate in position in a suitable fixture duringinstallation of the gib plate into the recess.

The bearing assembly upon being installed against the gib plate isproperly aligned within the bearing structure and remains preciselyaligned throughout the range of adjustment available.

The adjustment is carried out by means of a threaded adjustment elementpassing through a side of the recess and threadably engaging the bearingassembly cover with a locking element also provided to secure thebearing assembly in any adjusted position.

A mating pair of dished washers are preferably employed to accomodateslight changes in alignment of the adjustment threaded element whichoccur as the adjustments are carried out.

The installation is advantageously applicable to a plurality ofprepackaged bearing assemblies, each mounted within a respective recessof a common C-shaped cast bearing housing. Each recess opens inwardlyabout each leg of the C-shape such as to be able to be fit around asuitable supporting way structure with the adjustment element receivedwithin a cast-in web defining in part each recess or pocket.

The housing structure is premachined with suitable lubrication passagesdirected to each recess and passing within passages extending throughthe bearing cover to the space wherein the roller elements circulate.

The housing structure carrying the plurality of bearing assemblies isinstalled as a unit onto the structure to be supported such that theindividual bearing assemblies and thereafter the bearing heightadjustment carried out. Accordingly, each bearing assembly is notrequired to be precisely mounted to the supported structure, greatlysimplifying the installation thereon.

The present invention offers the advantage of greatly reduced assemblyand machining effort required in installation of individual bearingassemblies and eliminating the need for extensive machining of thesupported structure.

According to one aspect of the present invention a particular fixture isemployed in order to position the gib plates within the respectivehousing structure recesses so as to be subsequently secured in positionby means of applying a high strength moldable bonding material such as ametal reinforced epoxy resin, which holds the gib plates secure in theaccurately predetermined positions after setting up of the bondingmaterial.

The fixture comprises one or more locating arm members each having anend face adapted positionable such that with the gib plate heldthereagainst each gib plate is precisely located in the housingstructure. Each gib plate holding means preferrably is anelectromagnetic coil when energized securely but releasably attractingthe angled gib plate firmly against the end face of the locator arm. Oneor more of the locator arms may be movable on a carrier slide, in turnmovable into the housing to subsequently enable positioning each of theplurality of arms within a respective recess.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of supported and supporting machinestructures mounted together by roller bearing installations according tothe present invention.

FIG. 2 is an enlarged endwise view of a roller bearing installationaccording to the present invention with portions of the supported andsupporting machine structure shown in phantom fragmentary portions.

FIG. 3 is a fragmentary plan view of the roller bearing installationshown in FIG. 2 showing in section portions of the housing structurecomponent adjacent one of the bearing assemblies incorporated in theinstallation.

FIG. 4 is a view of a lengthwise section taken in FIG. 2.

FIG. 5 is a view of a transverse section taken in FIG. 3 showing aportion of the supporting machine structure with the bearing engagementthereon.

FIG. 6 illustrates an alternate embodiment of the bearing installationaccording to the present invention in end view.

FIG. 7 shows a side elevational view of the locating fixture utilized inconstructing the bearing installation according to the presentinvention, depicting the installation of the vertically opposed set ofgib plates.

FIG. 8 is a fragmentary enlarged view of the fixture shown in FIG. 7depicting the installation of the horizontally opposed set of gibplates.

FIG. 1 illustrates a typical application of the bearing installationaccording to the present invention in which a rectangular table orsaddle 10 comprising the supported structure is mounted for linearmotion on a supporting structure 12 comprised of spaced parallel ways 14extending beneath the table 10.

A bearing installation 16 is located at each corner of the table 10affixed beneath the table 10 and the open side of the C-shaped housingof each bearing installation receiving the parallel ways 14.

FIG. 2 shows the details of each bearing installation 16 which includesa generally C-shaped housing structure 18 affixed beneath the table 10and having a flange portion 20 having a number of tapped bores 22receiving fastening cap screws 25 extending through the table 10. Thetop and side surfaces 26 mate with corresponding machined surfaces onthe table 10 to provide accurate location of the housing structure 18.Alternatively, doweling or other methods of accurately locating thehousing structure 18 on the table 10 may be employed.

The housing structure 18 is preferably of cast iron construction andincludes a series of recesses 28 formed by casts in pockets, eacharrayed about each side of the C-shape, facing inwardly towards a way14. Installed in each recess 28 is a respective bearing assembly 30A,30B, and 30C, with two of the bearing assemblies, 30A and 30C, being inopposing relationship, such as to be able to exert a preloading pressureon the upper and under surfaces of bearing way 14. The ways 14 aremounted to the table supporting structure by means of cap screws 25, asshown.

A series of wipers are provided preventing entrance of foreign matterand confining the lubricant supplied through passages to be describedhereinafter on the way surfaces 32, 34, and 36 respectively. Thesewipers includes an upper side wiper 33 fastened along the upper lateraledge of the housing 18, including a wiping lip 35. A lower lateral wiper38 is secured with screws as shown to the lower side face of the housing18 having a wiping lip 40 engaging the under surface 36 of way 14.

Front and rear covers 42 and 44 are also provided (see FIG. 4) providedwith upper and lower wiper lips 44 and 46 at the front and upper andlower wiper lips 48 and 50 at the rear to wipe the surfaces 32 and 36.

Angled gib plates 52A, 52B, and 52C are precisely located within arespective recess 28A, 28B or 28C and firmly secured in thepredetermined position.

Angled gib plate 52A, 52B and 52C are each comprised of an inclinedsection 54 and a coextensive straight-sided guiding section 56. Thesurface 55 (FIGS. 4, 5) of the inclined section 54 is in engagement witha complementary inclined surface 58 formed atop each bearing assembly30.

FIG. 3 illustrates the means provided for establishing a lengthwiseposition adjustment of each bearing assembly 30 and a correspondingrecess 28, such that a depth (or height) adjustment may be achieved byengagement of the inclined surface 58 with the inclined surface of gibplate section 54. Such means is constituted by an elongated threadelement i.e., a cap screw 60, passing through a web 62 defining in parteach recess 28, through a bore 80 formed in web 62, with a suitablesufficient clearance provided therebetween to accomodate the slighttilting that occurs as the lengthwise position adjustment is executed.

Each cap screw 60 is threadably engaged with a bearing cover component72. The cap screw 60 is seated against a pair of dished washers 78 turnabutting the web 62 such as to prevent the capscrew 60 from moving tothe right as viewed in FIG. 4, capturing it to cause the lengthwisemovement of the bearing assembly 30 upon rotation thereof.

The consequence of the lengthwise adjustment of the bearing assemblyposition is an adjustment of the depth (or height) of the bearingassembly 30 by virtue of the engagement of the surface 58 with theinclined surface 55 of the gib plate section 54.

A locking element constituted by Allen screw 64 threadably received in abore in the web 62 is engagable against the end face of the associatedbearing assembly 30 to secure an adjusted position of the bearingassembly 30 when tightened thereagainst.

FIG. 4 illustrates the construction of each bearing assembly 30 astypified by the bearing assemblies 30A and 30C shown, which comprises atrack member 66 having a peripheral surface 68 providing a circulationbearing path for a plurality of roller elements 70.

The construction of each of the bearings 30 is preferably according tothe aforementioned U.S. Pat. No. 4,544,211, due to its superior trackingability under heavy loads.

The roller elements 70 are confined so as to circulate about the surface68 of the track member 66 by a two-piece cover 72 allowing theprotrusion of the roller elements 70 on one side of the bearing such asto enable rolling contact with the surface 34 of the way 14 as shown inFIG. 4.

The bearing cover 72 includes an upper member 74 formed with theinclined surface 58 which threadably receives the cap screw 60 forlengthwise position adjustment of the bearing assembly 30A as a whole.

The lower portion 76 of the cover 72 may be constructed of moldedplastic secured together by means of suitable fasteners as detailed inthe aforementioned U.S. patent.

The cap screws 60 are restrained by means of a dished washer pair 78which accomodates slight tilting of the capscrew 60 as the inclinedsurface 58 is drawn against the surface of the inclined section 54 ofthe gib plate 52.

A suitable clearance between bore 80 in web 62 and the capscrew 60accomodates the slight tilting of the capscrew 60.

Lubricant passages are formed in the housing structure 18 including apassage 84 exiting in a threaded fitting bore 86 which communicates witha cross passage 88 aligned with openings 90 in the gib plate section 54communicating with a recess 92. A bearing cover 74 associated with thelower bearing 30C has similar lubricant passages 84, 90, and recess 92machined through a plugged port 94.

FIG. 5 illustrates that recess 92 communicates with drilled passages 96communicating with the space in which roller elements 70 pass to directa flow of lubricant to the surfaces subject to rolling contact withinthe bearing 30, as also seen in FIG. 5.

The rolling elements 70 according to the aforementioned design describedin U.S. Pat. No. 4,554,211, are comprised of two different sets ofroller elements 70 separated by a spacer 98.

FIG. 5 also illustrates the construction of the gib plate 52, includingthe inclined section 54 and the guide section 56. The bearing assembly30A is urged sideways against the inside surface 57 of the guide section56 in order to align the bearing assembly 30A along the bearing axiswithin the housing 18.

This urging is established by means as may be constituted by a springloaded plunger assembly 100 disposed in a threaded socket 102 and turnbedded by means of a mass of bonding material 104 in a bore 106 formedin the housing 18.

A ball portion 108 acts on a lateral surface 65a of the track member 66to urge an opposite surface 65b thereof against surface 57 of the guidesection 56.

The gib plate assembly 52A is securely located in a preciselypredetermined position within a recess 28 by means of a mass of moldablebonding material 109 occupying a clearance space between a gib 52A and arecess 28.

The moldable bonding material must be of sufficient rigidity anddurability to rigidly locate the gib plate 52A therein while absorbingthe loads to be encountered.

A suitable material is a metal reinforced epoxy resin which iscommercially available and well known to those skilled in the art.

FIG. 6 shows that the bearing housing 18 may also be configured toaccomodate a fourth bearing set, in which an additional bearing 30D isprovided in a downwardly pendent section of the housing 18 so as toengage the way 14 on lateral as well as opposite upper and lower sidesurfaces thereof. This arrangement allows position adjustment of thesupported structure in the horizontal plane.

In such application the opposite array 16 on the other side of the tablestructure would omit the laterally spaced bearing assemblies 30B and 30Dand provide accurate lateral location of the bearing assembly by virtueof being guided on one of the rails 14.

FIGS. 7 and 8 show the use of the locating fixture used in making theinstallation according to the present invention, illustrated in makingthe bearing installation of FIG. 6.

The locating fixture 110 includes a fixture platform 112 having suitablelocating surface features 114, to allow accurate positioning of thehousing structure 18 according to the present invention, shown inphantom on the upper surface 116 of the fixture 112.

Each recess 28a, 28b, 28d is configured so as to receive a correspondinggib plate 52a, 52b, 52c, and 52d (also shown in phantom) in the properlocation with a clearance space 120 therebetween, as indicated.

For the four bearing installation, a two stage process is employed, withvertically opposed sets of gib plates 52A and 52C assembled in aseparate step from horizontally opposed sets of gib plates 52B and 52D.

A first carrier slide 122 is mounted on a pedestal block 124 fixed atopplate 112 for lengthwise sliding motion. A key 126 interfit with akeyway 128 maintains precise alignment, with a locating pin 129 movingagainst a locator block 130 at the correct operating position of thecarrier slide 122. A handle 132 may be provided to enable manualmovement of the carrier slide 122 into position.

A pair of locator arms 134, 136 are provided for respective gib plates52A and 52C, a first locator arm 134 fixed to the forward end of carrierslide 122, and a second locator arm 136 vertically slidable in thecarrier slide 122. Each locator arm 134 and 136 has formed on the endthereof an angled end surface 138 and 140 respectively, exactlycorresponding to the inclined sections 54A, 54C of the gib plates 52Aand 52C respectively; and also a side surface 142 and 144 correspondingto the guide sections 56A and 56C thereof.

An electromagnet 146 and 148 is mounted in each locator arm 134 and 136adjacent the end thereof, adapted to be selectively energized from asuitable power supply circuit 150, to securely hold a respective gibplate 56A and 56C against surfaces 138, 140, 142, 144.

The locator arm 136 is slidably mounted to be able to be elevated as thecarrier slide 122 is moved into the housing structure 18, so as to clearthe otherwise interfering portions of the housing. Afterwards, thelocator arm 136 is lowered, as by a rotation of a threaded thumbscrew152 mounted in offset plate 154 affixed to the upper end of the locatorarm 136 until a locator pin 156 comes to rest atop the carrier slide122, which is precisely located to very accurately position the surface138.

In practice, the housing structure 18 is positioned on surface 116against the locating surfaces 114. Metallic epoxy resin is applied ineach recess 28A and 28C.

Gib plates 52A and 52C are positioned against surfaces 138, 140, 142,144 and the electromagnets 146, 148 energized.

The carrier slide is advanced to move the gib plate 52C into position inrecess 28C, embedded in the mass of bonding material. Thereafter,locator arm 136 is lowered to move gib plate 52A into position in recess28A, also embedded into the mass of bonding material.

The bonding material is allowed to set up, and thereafter theelectromagnets are deenergized to release the gib plates 52A and 52C andallow withdrawal of the locator arms 134, 136.

FIG. 8 shows that a second carrier slide 160 is employed for the secondstage, which also carries a pair of locator arms 162, 164, both slidablevertically in the carrier slide 160. Each locator arm 162, 164 isadapted to hold and position a respective gib plate 52B, 52D in similarfashion to the above described locator arms 134, 136, and thus areformed with respective inclined surfaces 166 and 168, and surfaces 170and 172, adapted to receive sections 54 and 56 of the gib plates 52B,52D.

Electromagnet coils 174, 176 are provided adjacent to these surfaces,selectively energized by power supply circuit 150 to create a magneticholding force when energized to securely hold the respective gib plates52C, 52D in position thereon.

Each locator arm 162, 164 is also likewise provided with thumbscrews 178and 180 respectively mounted in offset plates 182 and 184 respectivelyfixed atop each locator arm 162, 164 to allow lowering onto a locatorpin 186, 188 after carrier slide 160 is moved into position.

As before, a moldable bonding material, preferably a metallic epoxyresin, is emplaced in the recesses 28B, 28D prior to moving the gibplates 52B, 52D thereinto, magnetically clamped to the ends of thelocator arms 162, 164.

After the epoxy has set, the electromagnetic coils 174, 176 aredeenergized to release the gib plates 52B, 52C and allow withdrawal ofthe locator arms 162, 164 and carrier slide 160.

It can be appreciated that very accurate location of all of the inclinedand guiding surfaces are thereby achieved very expedetiously, ascompared to conventional machining processes.

The bearing installation may be mounted as an assembly by accuratelocation of the housing as a whole on the table, with the bearings eachadjusted to establish a position adjustment of the supported structureand thereafter proper bearing preload by adjustment of the opposingbearing assembly.

Maintenance is greatly simplified, since individual bearings can bereplaced without dissassembly or reworking of the major machinestructural components.

We claim:
 1. A method of installing a roller bearing assembly (30) ofthe type including a track member (66) defining a track surface (68) forrecirculation of a series of roller elements, (70) with a bearing cover(72) enclosing said track member (66) to confine said roller elements(70), but with said roller elements (70) exposed on one side so as to beable to roll on a supporting surface (34), said bearing assembly (30) tobe installed in a structure (18) supported on a linear surface (34) of asupporting structure (14) by said bearing assembly (28), comprising thesteps of:fabricating a housing structure (18) with a recess (28) formedtherein defined by a bottom and a plurality of sides to be able toreceive said roller bearing assembly (30) so as to adjoin the bottom ofsaid recess (28) and extending past the sides of said recess so that therollers protrude out of said recess (28); fabricating an angled gibplate (52) comprised of an inclined section (54) and a straight guidesection (56) extending alongside each other; forming an inclined surface(58) on the top of said bearing assembly (30) corresponding to saidinclined gib plate section (54), and a guide surface (67) on the side ofsaid bearing assembly parallel to said bearing axis; locating said gibplate (52) in a predetermined position in said recess with said inclinedsection extending along the bottom of said recess and said straightguide section extending along one side of said recess; fixing said gibplate (52) in said predetermined position in said recess; installingsaid roller bearing assembly (30) in said housing structure (18) withsaid inclined and guide surfaces (58, 67) against surfaces (55A) of saidgib plate inclined and guide sections (54,56); mounting said housingstructure (18) to said supporting structure (14) with said guidesurfaces (57, 67) aligned with the direction of relative travel; and,adjusting the position of the roller bearing assembly (30) in saidrecess along the direction of said bearing axis to obtain proper bearingassembly depth by movement along and in engagement with said inclinedsection (54) and guide section (56) of said gib plate (52) and fixingthe roller bearing assembly in said recess in said adjusted position byconnecting (60,64) said roller bearing assembly to said housingstructure to prevent relative movement therebetween in either directionalong said bearing axis.
 2. The method according to claim 1 wherein saidstep of locating said gib plate (52) includes the step of holding saidgib plate (52) on a fixture (110) accurately located against saidhousing structure (18).
 3. The method according to claim 2 wherein saidstep of fixing said gib plate (52) comprises the step of moldingsettable bonding material (109) against said housing structure (18) andsaid gib plate (52) while holding said gib plate (52) in position withsaid fixture, and releasing said gib plate (52) from said fixture (110)after setting of said bonding material (110).
 4. The method according toclaim 1 wherein said bearing assembly (30) is constantly urged against asurface (57) of said gib plate guide section (56) to align said bearingassembly (30) in said housing structure (18).
 5. The method according toclaim 1 wherein said housing structure (18) is fabricated by casting,with a series of webs (62) forming a pocket comprising said recess (28).6. The method according to claim 1 wherein a plurality of bearingassemblies (30A, 30B, 30C) are each installed in said housing (18) in arespective recess (28A, 28B, 28C).